The vaseline gap voltage clamp technique will be used to study the ionic channels underlying membrane excitation of rat and human skeletal muscle. The aims are twofolds: 1) To obtain a quantitative description of the behavior of the major ionic channels in normal human muscle. This will serve as a reference for future studies of possible membrane-related human muscle disease. 2) To perfect the vaseline gap technique so it can be used on specimens obtained from routine human muscle biopsies. We will perfect our technique on rats, then proceed to human muscle. A digital computer will be used to acquire and analyze our data, to perform model calculations and to build a reference data base for future studies of diseased muscle.